I Think I Love You

Written by Tony Romeo as the debut single for the fictional musical TV family, this song topped Billboard's Hot 100 for three weeks in November and December 1970 and was later certified by NARM as the best-selling single of 1970. Released in August 1970—a month before the ABC-TV sitcom premiered—the single features Shirley Jones and David Cassidy, with Cassidy as lead vocalist, and also reached number one in Canada and Australia.